When paints are applied manually or automatically to objects, a substream of the paint, which generally contains both solid bodies and/or binding agents as well as solvents, is not applied is to the object. This substream is known among experts as “overspray”. In the broader sense, the terms overspray, overspray particles or overspray solids are always referred to within the context of a disperse system, such as an emulsion or suspension or combination thereof. The overspray is taken up by the air flow in the paint booth and supplied for separation so that, if required, the air can be conveyed back to the coating booth after suitable conditioning.
Particularly in systems with a relatively high paint consumption, for example in systems for painting vehicle bodies, wet separation systems on the one hand or electrostatically operating dry separators on the other are preferably used in known manner. In known wet separators, a relatively high amount of energy is needed to circulate the very large quantities of water required. Treating the rinsing water is costly due to the elevated use of paint-binding and detackifying chemicals and the disposal of paint sludge. Furthermore, owing to the intensive contact with the rinsing water, the air absorbs a high amount of moisture which, in recirculating-air mode, in turn results in a high energy consumption for treating the air. In electrostatically operating dry separators, the paint overspray has to be continuously removed from the separation surfaces, which generally involves very complex structural measures and can therefore be susceptible to faults. Moreover, the energy consumption in such separators is relatively high.
As an alternative to these separation systems, devices of the type mentioned at the outset are known, which operate using exchangeable filter modules which can be exchanged for unladen filter modules and disposed of or possibly recycled after an overspray loading limit is reached. In terms of the energy used and the resources required, the treatment and/or disposal of such filter modules can be more acceptable than the expense linked to a wet separator or an electrostatically operating separation device.
In known separation devices of this type, such as those described for example in DE 20 2005 013 403 U1, the separation units are frequently arranged next to one another and form a type of filter wall which is acted upon by the overspray-laden booth air. Suitable separation units are described for example in AT 411 331 B. Before the booth air arrives at the inlet of a separation unit, however, it flows over the outer housing regions of the separation unit at which overspray is already separated. Over the course of time, this causes the mutually adjacently arranged separation units to stick to one another which in turn makes it difficult for them to be exchanged, and in particular to be exchanged in a desirable automated operation.